Cable Entry Device Comprising Means for Adjustment

ABSTRACT

A cable entry device for providing sealing in a space between a cable and a surrounding material. The cable entry comprises a covering, and a first and a second sealing member for receiving said material therebetween. The first sealing member provides a biasing force on the covering when inserted into a hole of the material, wherein the second sealing member is urged towards a surface of said material.

TECHNICAL FIELD

The present invention relates to a cable entry for a conduit or cable,and more particularly a cable entry for providing sealing in a spacebetween a cable and a surrounding material.

BACKGROUND OF THE INVENTION

When a cable or conduit is inserted through a hole of a material, thereare a number of methods available for protecting the cable againstdamage and sealing one side of the material from the other. If the cableis inserted into the interior atmosphere, of e.g. a cubicle, from theambient atmosphere, a hole is made in the cubicle for inserting thecable.

A rubber cable entry or grommet may be tightly inserted into the hole ofthe cubicle, and a cable can be inserted into the cable entry, causingsealing of the interior atmosphere of the cubicle from the surroundingatmosphere. However, this type of cable entry provides no locking of thecable to the cable entry. Also, it provides no locking of the cableentry to the surrounding material and may relatively easy be pushed outof the hole. The rubber cable entry known in the art comprises flangesbetween which the material, in which the cable entry is inserted, isreceived. The flanges are extending outwardly from the hole onrespective sides of the material to provide sealing. However, when thecable entry is inserted into the hole, one of the flanges has do bepushed through the hole. The material of the flange has to be compressedto pass through the hole. Alternatively, a portion of the flange ispushed through the hole at the time, wherein the material of the flangedoes not have to be compressed as much. However, assembling of such acable entry is cumbersome, especially for an assembler, who might fithundreds of cable entries each day. Still another problem with therubber cable entry is that it only fits material having a predeterminedthickness. Different thickness requires different cable entries.

Another cable entry known in the art solves the problems of locking itto the surrounding material, and locking of the cable to the cableentry. Such a cable entry is generally made of a solid material,comprising several constituent parts, with a flexible sealing core. Toconnect the cable entry to e.g. a cubicle, a cylindrical main part ofthe fitting has to be provided with a sealing-ring before being enteredinto a hole of the cubicle. Furthermore, the main part is provided withthreads, for locking the main part to the cubicle by a threaded nut.Alternatively, the surrounding material itself is threaded. Inside themain part is a bushing provided for sealing the space surrounding thecable. Also, the main part is provided with gripping tongues, whichpress the bushing towards the cable, causing both sealing and locking ofthe cable, when a cap is threaded onto the main part.

There is a problem with the cable entry providing locking in that itcomprises several constituent parts, have a space-consuming design andis cumbersome to assemble. Also, when the cable is inserted into thecable entry and the cap is threaded to press the tongues towards thecable, the cable may not be completely locked, since the cable can slipin either direction if pulled, and the tongues may damage the coating ofthe cable. Furthermore, although the cable entry is manually adjustableto surrounding material of different thickness, assembling of the cableentry using the nut may be cumbersome, especially if it is assembled ina narrow space.

SUMMARY OF THE INVENTION

It is an object of the present invention to provide a cable entry thatis self-adjusting within a predetermined range to the thickness of asurrounding material, to which the cable entry is to be connected.

The above object is achieved by a cable entry according to the inventionfor providing sealing in a space between a cable and a surroundingmaterial. The cable entry comprises a covering, and a first and a secondsealing member for receiving said material therebetween. The firstsealing member provides a biasing force on the covering when insertedinto a hole of the material. Thus, free ends of the first and secondsealing members abut a first and a second side of a material,respectively, when inserted into a hole therein.

The first sealing member may extend outwardly from a first end of thedevice towards the second sealing member, and the second sealing membermay extend outwardly from a second end of the covering towards the firstsealing member.

Further embodiments of the invention will appear from the dependentclaims.

It is an advantage of the present invention that it is automaticallyadjusted to the thickness of the material received between the sealingmembers. Thus, one cable entry may fit a range thickness, wherein thetotal number of different cable entries to be provided by a manufacturermay be decreased.

BRIEF DESCRIPTION OF THE DRAWINGS

Further objects, features, and advantages of the invention will appearfrom the following description of several embodiments of the invention,wherein various aspects of the invention will be described in moredetail with reference to the accompanying drawings, in which:

FIG. 1 is a perspective view of a cable entry device;

FIG. 2 is a cross-sectional view of a cable entry with a cable insertedtherein;

FIG. 3 is a perspective view of a first embodiment of a core comprisingmeans for strain relief;

FIGS. 4 a and 4 b are perspective views of a second embodiment of a corecomprising means for locking the core;

FIG. 5 is a cross-sectional view of a covering;

FIG. 6 is a cross sectional view of another embodiment of the covering;

FIG. 7 is a cross sectional view of another covering enclosing the coreof FIGS. 4 a and 4 b; and

FIGS. 8 a and 8 b are cross-sectional views of a cable entry comprisinga core, a covering and detachable means for strain relief.

DETAILED DESCRIPTION OF THE INVENTION

When a cable 1 is inserted into e.g. a cubicle, there are internationalstandards for tightness classification, such as the IP classificationsystem, that specify to what degree the internal atmosphere of e.g. acubicle shall be sealed from the ambient atmosphere or fluid. Also,there are physical situations that require a cable 1 to be locked to acertain extent to the cubicle, to provide strain relief. A cable entryor locking grommet is provided for insertion into a hole of a material.

FIG. 1 illustrates a first embodiment of a cable entry device 100.

FIG. 2 illustrates a first embodiment of a cable entry 100 incross-section with the cable 1 inserted into it. The cable entrycomprises a core 110 enclosed by a covering 200, preferably made of anelastomer, adaptable to a surrounding material for sealing a spacebetween the cable and the material. As should be noted, the cable entrymay in different embodiment be provided with a core, wherein in otherembodiments the cable entry does not have a core.

FIG. 3 discloses a first embodiment of the core 110. The core 110comprises an intermediate portion 111 or support element extendingaxially, which may provide lateral support of the core 110. Lockingmeans is connected to an outer periphery of the intermediate portion illfor instantly connecting the core, and the covering surrounding it, tothe surrounding material when it is inserted into a hole therein. Inthis embodiment, the locking means comprises a flange 112 and detents113 a, 113 b connected to the intermediate portion 111. When the core isinserted into a hole of a material, the diameter of the hole is lessthan the diameter of the flange 112. Also, the distance between freeends of the detents 113 a, 113 b is larger than the diameter of thehole. The diameter of the intermediate portion 111 is less than thediameter of the hole.

The core of FIG. 3 is preferably made of a plastic having a certainflexibility, such as a polyamide, e.g. PA 6, that is soften by asoftener, which makes the plastic tough.

The detents 113 a, 113 b are connected to the intermediate portion 111at one end thereof, and extend from the intermediate portion towards theperiphery of the flange 112. Due to the material of the core 110 havinga certain flexibility, the free ends of the detents 113 a, 113 b whenpushed through a hole, are urged towards the intermediate portion 111.Thus, the distance between said free ends will be less than the diameterof the hole. Thus, by simply pushing the core through the hole of amaterial, the free ends of the detents 113 a, 113 b will bee urgedtowards the intermediate portion. When fully through the hole, the freeends of the detents 113 a, 113 b, will return to their initial position.Thus, the core is locked to the surrounding material by means of thedetents 113 a, 113 b and the flange 112, which forms a stop when thecore 110 is pushed into the hole. The flange 112 prevents that the core110 can be pushed through the hole in one direction, preferably from theinterior to the exterior of the cubicle. The detents 113 a, 113 bprevents the core to be pushed back through the hole in the reversedirection.

According to one embodiment of the core 110, it may have means forproviding strain relief. At the inside of the intermediate portion 112are provided radially spaced flexible locking tongues 17 slightlydirected in the direction of insertion of the cable 1. When the cable isinserted into the core 110 the tongues will abut the cable. Pulling thecable in the reverse direction will increase the pressure from thetongues towards the cable, wherein the strain relief is provided. Thelength of the tongues may vary, as will be explained below.

FIGS. 4 a and 4 b disclose another embodiment of a core 150. The core150 is preferably made of a rigid material, such as a plastic accordingto above. The core comprises a first and a second intermediate portion151 a, 151 b, and locking means for locking the core 150 to asurrounding material when inserted into a hole thereof. The lockingmeans comprises a flange 152 and a first and second detent 153 a, 153 b.The flange 152 corresponds to the flange disclosed in FIG. 3. Thedetents 153 a, 153 b are connected to legs or flexible portions 154 a,154 b.

The flange 152 is connected to a first end of the intermediate portions151 a, 151 b. The intermediate portions 151 a, 151 b extendsubstantially perpendicular from an inner periphery of the flange 152.The length of the flexible portions 154 a, 154 b correspondsubstantially to the length of the intermediate portions 151 a, 151 b.The detents 153 a, 153 b are connected to an upper portion of theflexible portions 154 a, 154 b, and extends therefrom towards the outerperiphery of the flange 152. From a tip 155 a, 155 b of the detents asupport surface 156 a, 156 b extends towards the flexible portions 154a, 154 b. A support surface 157 of the flange 152 and the supportsurface 156 a, 156 b of the detents 153 a, 153 b are substantiallyparallel.

A base 158 of the flexible portions 154 a, 154 b, are connected to theintermediate portions 154 a, 154 b adjacent to the flange 152. Thus,although the inherent material characteristics of the core 150 are quiterigid, the width and thickness of the base 158, and the positionthereof, provide flexibility of the flexible portions in the lateraldirection of the core. In operation, as the support surface 157 of theflange 152 and the support surfaces 156 a, 156 b of the detents 153 a,153 b are substantially perpendicular, the forces exerted on theflexibly portions 154 a, 154 b are substantially in the longitudinaldirection of the flexible portions. Thus, the thickness of the base 158may be dimensioned to comply with strain relief requirements.

When at least the intermediate portions 154 a, 154 b are enclosed by acovering, as disclosed below, the flexible portions 154 a, 154 b, aresupported at an inner and outer side of the core 150 by said covering.Thus, the core, which is flexible, allows the flexible portions 154 a,154 b to be urged towards the center of the core 150 when pushed throughthe hole, allowing the detents 153 a, 153 b to pass through the hole.When fully through, the covering will return the flexible portions totheir initial position, wherein the detents instantly connect the core150 to the surrounding material. The core, and the covering, may easilybe detached from the material surrounding it, wherein the cable entrymay be reused. The core and the covering may be detached simply bypushing the detents 153 a, 153 b inwardly towards the center of thecore, wherein it may be removed from the hole.

The thickness of the base 158 may be thinner than the remainingthickness of the flexible portions 154 a, 154 b. Thus, the flexibilitymay be further increased, whereas the material of the core 150 may beeven more rigid. To obtain a good flexibility, the thickness of the base158 is approximately 50% of the thickness of the flexible portions 154a, 154 b. However, the relationship may be smaller or larger, or evensubstantially similar, depending on the requirement of flexibility andstrength.

The flexible portions 154 a, 154 b, may be provided by forming slots inthe intermediate portions 151 a, 151 b.

In the embodiments shown in FIGS. 3, 4 a and 4 b, the intermediateportions 111, 151 a, 151 b are substantially cylindrically shaped andextending substantially perpendicular from the inside of the flange 112,152 in the longitudinal direction of the core 100, 150. However, theintermediate portions 111, 151 a, 151 b may also be slightly conicallyshaped. The intermediate portions 111, 151 a, 151 b may alternativelyhave a polygonal cross section, as long as it fits into a hole of amaterial. Furthermore, the flange 112, 152 may be divided into sectionsforming several individual flanges circumferentially spaced around theintermediate portions 111, 151 a, 151 b. Also, any number of detents 113a, 113 b, 153 a, 153 b, which provide sufficient locking of the core, ispossible.

By altering the distance between the detents 113 a, 113 b, 153 a, 153 band the diameter of the flange 112, 152, core 110, 150 may be adapted toholes of different diameter. Furthermore, by altering the distancebetween the free end/tip of the detents 113 a, 113 b, 153 a, 153 b andthe flange 112, 152, the core 110, 150 may be adapted to material ofdifferent thickness.

FIG. 5 discloses the covering 200 for enclosing the core 110, 150. Inthe outer circumference of the covering 200 a recess 210 is provided forreceiving the surrounding material when the cable entry is inserted intoa hole. The recess 210 provides first and second flexible sealingmembers, such as flanges 220, 230 on opposed sides of the recess 210,for sealing the space between the covering and the surrounding material.

The covering 200 has first and second circular cuts 240, 241 provided ona first and second end portion of the covering 200, respectively. Acavity 242 is formed between the end portions. The end portions togetherwith the cavity 242 form a passage, in which the cable 1 is to beinserted.

The first end of the covering surrounding the upper cut 240 forms aflexible collar 243, creating a tight seal between the covering 200 andthe cable 1 when the cable 1 is inserted through the first cut 240.

At least one boss (not shown) may be provided on the inside of thecollar 243. An early release of vacuum in the cavity 242 is provided bythe boss when the tool forming the cavity is pulled out of the first cut240 during manufacturing. This allows for the manufacture of a very thinmembrane, forming a penetrable seal (not shown) of the second cut 241.The penetrable seal can be removed by simply penetrating the cable 1trough the seal rather than using a tool to create a circular hole. Thepenetrable seal makes it possible to seal a hole in the materialsurrounding the covering 200 even if the cable 1 is not insertedtherein. The penetrable seal may alternatively be provided at the firstcut 240. Thus, the boss may be provided at the inside of the second cut241.

The cavity 242 comprises a circumferentially extending slot 260 forreceiving the flange 112, 152 of the core 110, 150. The inner surface ofthe cavity 242 will enclose the intermediate portions 111, 151 a, 151 b.The detents 113, 153 a, 153 b will extend out of cuts (not shown) of thecovering when enclosed thereof.

When the core 110 is enclosed by the covering 200, a cylindrical lip 246may enclose the tongues 114. The lip 246 is connected to covering at theside of the second cut 241 extending therefrom towards the intermediateportion 111. When the cable 1 is inserted into the second cut 241 thetongues 114 enclosed by the lip 246 are abutting, but not damaging, thecable 1. Alternatively, the lip 246 is partly slit open. Furthermore,the space between the cable 1 and the covering is sealed when the cable1 is inserted therein.

The tongues 114 and the lip 246 provide a sealed locking of the cable 1to the cable entry, which locking is instant when the cable 1 isinserted into the cable entry.

The covering 200 is provided with a cut (FIG. 1) for receiving thedetents 113 a, 113 b, 153 a, 153 b. Thus, the detents 113 a, 113 b, 153a, 153 b are not encapsulated by the covering 200 and can directly abutagainst the surrounding material.

The second end of the covering 200, to be pushed through a hole in thematerial, has a diameter, which is less than the diameter of the hole.Furthermore, the second sealing member 230 extends outwardly from thesecond end of the covering towards the free end of the first sealingmember 220. At the free end of the second sealing member 230 thediameter is larger than the diameter of the hole. When pushed throughthe hole, the second sealing member 230 will be urged towards the centerof the covering 200, wherein the cable entry is easy to insert into thehole of the material, due to the recess 210 between the second sealingmember 230 and the center portion of the covering 200.

When the cable entry is inserted into the hole of the material theflexible first sealing member 220 of the covering 200 is extendingoutwardly from an edge of a first side of the material surrounding thehole. When the free end of the first sealing member 220 meets thematerial it is compressed and slides outwardly from the hole as thecable entry is further pressed through the hole. When the second sealingmember 230 is fully through the hole, the first sealing member providesa biasing force on the covering urging the second sealing member towardsa second side of the material surrounding the covering 200. Thus, thespace between the covering 200 and the surrounding material is sealed,as the free ends of the sealing members 220, 230 abut the materialreceived therebetween. If the covering 200 encloses a core, the covering200 is locked to the hole of the material by means of the locking means,and a seal to both sides of the surrounding material is provided.

In another embodiment, locking means is provided as an integral part ofthe covering as solid rubber or elastomer detents. However, thearrangement of these detents is substantially the same as the detents asset forth above, albeit formed as integral with the covering. Thus, theelastomer detents are extending outwardly towards the first sealingmember 220 of the covering 200 for providing locking of the coveringaccording to the same principles as set out above. If the coveringcomprises a core, the intermediate portion is provided with cut-inportions for receiving each of the elastomer detents when the cableentry is inserted into a hole.

FIG. 6 discloses another embodiment of a covering 400 according to theinvention. A recess 410 is provided in the outer circumference of thecovering 400 for forming first and second sealing members 420, 430, suchas flanges. The covering 400 may comprise means for receiving a secondsealing member 430 during insertion of the covering into the hole. Oneside of the recess 410, which is outwardly facing the sealing members420, 430 and inwardly facing the intermediate portion of the core, whenreceiver therein, or the cavity, has an irregular surface 440. A firstportion 441 of the irregular surface 440 has a diameter, which is largerthan the diameter of a second portion 442 of the irregular surface 440.The second 442 portion may be formed as a recess of the covering 400 orthe first portion 441. The first portion 441 faces outwardly an innerside of the first sealing member 420. The second portion 442 facesoutwardly an inner surface of the second sealing member 430. Thedifference in diameter between the first and second portions 441, 442corresponds substantially to twice the thickness of the second sealingmember 430 of the covering 400. Thus, when the covering 400 is pressedthrough a hole, the second sealing member 430 is received within thesecond portion of the irregular surface 440, wherein it is even easierto press the covering through the hole as the covering 400 does not haveto be compressed at all. The diameter of the first portion 441 of theirregular surface 440 is less than the diameter of the hole. Thediameter of the first portion 441 is preferably only slightly less thanthe diameter of the hole, wherein the covering 400 is fitted to thesurrounding material. Correspondingly, the diameter of the secondportion 442 of the irregular surface 440 plus twice the thickness of thesecond sealing member 430 of the covering 400 is slightly less than thediameter of the hole.

The length of the first portion 441 of the irregular surface 440, andthe total length of the irregular surface 440 is dimensioned such thatsaid first portion will extend at least partially through the hole whenthe covering is inserted therein. Thus, when the sealing members 420,430 extend outwardly from the hole, the covering will be laterallysupported by the first portion 441.

The recess 410 and the sealing members 420, 430 according to theembodiment shown in FIG. 6 provide instant adjustment of the covering todifferent thickness, within a predetermined range, of the surroundingmaterial when the covering is pressed through a hole thereof. The firstsealing member 420 extends outwardly from the upper end of the covering.The second sealing member 430 extends outwardly from the second end ofthe covering 400. The thickness of the sealing members 420, 430 is suchthat they are flexible at least 90 degrees relative the irregularsurface 440. When the covering 400 is inserted into a hole, the freeends of the sealing members 420, 430 will automatically slide outwardlyfrom the hole. The distance between the connection points of the sealingmembers 420, 430 determines the range of material thickness, to which aspecific covering is suitable.

If the covering 400 comprises a core 110, 150, the distance between thesupport surfaces 155 a, 155 b of the detents 113 a, 113 b, 152a, 153 band the size of the recess 410 determine the range of materialthickness, to which a specific covering is suitable.

FIG. 7 discloses a cable entry 500 comprising a covering 510 and a core150. Parts of the covering 510 not explicitly described with regard toFIG. 7 correspond to the parts described with regard to FIG. 6. Thecovering 510 comprises strain relief means integral with the covering.On an inner side of a first end 520 of the covering 510 facing a cavity530 of the covering 510 are provided hooks 540 for abutting the cablewhen inserted into the cavity. When the cable is inserted, the hooksbeing flexible are urged towards the periphery of the covering 510. Whenthe cable is pulled in the reverse direction, a friction between thecable and the hooks 540 will provide strain relief. The harder the cableis pulled in the reverse direction, the greater is the friction up to acertain amount. The amount of the friction is dependent of the numberand material of the hooks 540, and the material of the covering of thecable.

A conically shaped second end 550 opposing the first end 520 of thecovering 500 may have means for providing strain relief. At the top endof the conically shaped portion is an inwardly facing circular surface560 provided. The circular surface extends substantially in thelongitudinal direction of the covering 510, i.e. in the direction ofinsertion of the cable. When a cable is inserted through the covering510, the circular surface will abut the cable, wherein a friction iscreated therebetween. When the cable is pulled in the reverse directionthe friction will cause the conically shaped portion 550 to becompressed. Thus, a certain strain relief will be provided, the amountof which depending on the size and type of material of the circularsurface 560, and the material of the cable. To further increase thestrain relief, protrusions 570 may be provided at the outer periphery ofthe top end of the conical portion 550. When the cable is pulledbackwards, the protrusions 550 will cause the circular surface 560 toremain parallel with the cable, wherein the friction is maintained. Aslong as the conically shaped end 550 does not collapse, i.e. extend inthe reverse direction of insertion of the cable 1, strain relief will beprovided.

If the covering 500 of FIG. 7 comprises a core 150, the conical end 560when compressed will be urged towards the flange 152 of the core 150.Thus, the covering is more rigid when enclosing a core, wherein it isheavier to compress the conical portion 550. Thus, the strain relief maybe even further improved.

FIGS. 8 a and 8 b disclose a cable entry 600 having a core 610 and acovering 620. A detachable strain relief means 630 may be attached atone end of the cable entry 600 to the core 610. The strain relief meanscomprises tongues 640 as disclosed above. The length of the tongues isalternating shorter and longer. Thus, the strain relief means fit cablesof different size. The strain relief means may comprise two equal halvessnap fitted to the core 610. The strain relief means may be detachedwhen the cable is inserted into the cable entry 600, wherein the cablemay be removed from the cable entry.

A cable entry may not comprise the core. Thus, the covering as disclosedabove may be used without the core, wherein several advantages may stillbe provided, such as the irregular surface for easy push trough and/orthe self-adjustment to different thickness.

The core and covering is disclosed as circular. However, they mayequally be quadrilateral or polygonal depending on the form of the holeinto which they should fit.

The covering is made of a flexible material, such as an elastomer, e.g.TPE (thermoplastic elastomer), EPDM (Ethylene-Propylene-Diene-Monomer),or chloroprene.

The present invention has been described as applicable to a cubicle byway of example. However, the invention is not limited to this singleapplication, it is also applicable to holes of many other applications,such as electrical control cubicles, instrument housings, householdappliances, cable entries in walls, conduit entries etc. Also, forsimplicity reference has been made to a cable, which is not intended tolimit the scope of the invention. As is understood, the invention mayequally be used with e.g. a conduit for conducting fluids, or a wire.The scope of the invention is best defined of the appended independentclaim.

1. A covering for cable entry device for providing sealing in a spacebetween a cable and a material surrounding the device, comprising afirst and a second sealing member, which are formed by a recess of theouter periphery of the covering, for receiving said materialtherebetween, wherein the first sealing member provides a biasing forceon the covering when inserted into a hole of said material.
 2. Thecovering according to claim 1, wherein the first and second sealingmembers are flexibly connected to the covering.
 3. The coveringaccording to claim 1 wherein the circumference at a free end of thefirst sealing member is larger than the circumference of a free end ofthe second sealing member.
 4. The covering according to claim 1, whereinfree ends of the first and second sealing members abut a first and asecond side of the surrounding material, respectively, when the coveringis inserted into a hole therein.
 5. The covering according to claim 1,wherein the first sealing member extends outwardly from a first end ofthe covering towards the second sealing member and the second sealingmember extends outwardly from a second end of the covering towards thefirst sealing member.
 6. The covering according to claim 1, wherein thecovering comprises means for temporarily receiving the second sealingmember during insertion into a hole.
 7. The covering according to claim6, wherein the means for temporarily receiving the second sealing membercomprises a recess of the covering having a depth corresponding to thethickness of the second sealing member.
 8. The covering according toclaim 6 wherein the means for temporarily receiving the sealing membercomprises an irregular surface of the covering having a first and asecond portion, the first portion having a diameter corresponding to thediameter of the hole, to which the device is dimensioned for, and thediameter of the second portion plus twice the thickness of the secondsealing member correspond to the diameter of said hole.
 9. The coveringaccording to claim 8, wherein the second portion (441) will extend atleast partially through the hole when the covering is inserted therein.10. Use of the covering according to claim 1 as a cable entry device.